| 摘要 |
<p>PURPOSE:To remove volatile matters from a polymer effectively, by bringing the polymer in a molten state into contact with an extractant. CONSTITUTION:In a process wherein volatile matters contained in a thermoplastic polymer is removed by treating the polymer with an extractant under a high pressure, the polymer in a molten state is brought into contact with the extractant. Here, the term 'the polymer in a molten state' means a liq. polymerization compsn. of the polymer, the melt of powder or pellets of the polymer, or a mixture thereof. As the extractant, any of carbon dioxide, nitrous oxide, carbon disulfide, an aliphatic hydrocarbon such as ethane, ethylene or propane, a halogenated hydrocarbon, an aromatic hydrocarbon such as benzene, toluene or xylene, and an alcohol such as methanol or ethanol can be used. They are used in a liq. or supercritical state; the latter is pref.</p> |
